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Beating under headsail
Posted: Sun Jun 03, 2012 8:48 pm
by Silkie
I used to do this quite a bit since it took me a remarkably long time to learn just how much difference an inch either way on the sheets makes

but that's another story.
I'd been broad reaching/running this morning in quite a fluky fresh breeze and knew I'd come on to the wind for the last couple of miles but decided to stick with just the genoa. I'd probably have needed a reef with the main up but the full genoa sheeted against the spreaders was just fine and so well balanced that I was steering with finger and thumb and could take my hand off the tiller for brief periods before she started to turn slowly into the wind. In the gusts she heeled a bit more and went a bit faster with almost no tiller input required - it's quite a different story with the main up.
I'm sure we were just as close-winded as with the main and although we were slower it's hard to judge how much with my dirty bottom. I spose we could have been making more leeway (?) but I wasn't paying attention.
Does anyone else do this regularly?
Re: Beating under headsail
Posted: Sun Jun 03, 2012 10:30 pm
by Clyde_Wanderer
I have sailed up wind in this fassion in the past and have sailed very close.
I have discovered that the lower spreaders on the new mast are much wider than the old spreaders which puts a limit on how close I can hawl in the genoa.
The last two solo passages have been with main and genoa, the first one was full main and full gen and up to 15kts wind and I noticed that she could sail up with the windex arrow well inside the indicator which allowed me to sail very close during squally moments which gave me the oppertunity to get up closer to my destination and saved a couple extra tacks.
On the down side the more she heels the more speed she losses which I guess is to be expected.
Today I sailed with two reefs in the main and full genoa with some heavy squalls sailed from Millport bay clockwise around wee Cumbrae over to Rubh an Euan and back through the Tan to Fairlie and am completly knackered now after dozens of tacks.
The boat definatly seems to be easier to sail with both sails since the new mast was fitted, or maybe its all in the head regarding confidence and a lighter mast.
I would guess that HB can sail as close as 35deg to the wind although that is juggling heading and speed.
C_W
Re: Beating under headsail
Posted: Mon Jun 04, 2012 8:49 am
by jim.r
I suspect the reason is that with just the genoa up the shape is better and the leading edge cleaner than with 2 sails up where both will be reefed to reduce the sail area? THe only issue , I believe, is that this can cause the mast to pant in heavy weather with potential stress issues. I'm thinking of getting an emergency forestay fitted so I can use a #3 or #4 on it when otherwise I'd have a heavily reefed genoa.
Re: Beating under headsail
Posted: Tue Jun 05, 2012 10:11 am
by mm5aho
I often sail with just genoa, moreso in moderate or high winds. Boat seems more balanced, and tiller is very light. Its easier managed, good for singlehanding, and performance (speed and angle) seems very comparable.
Easier reefed than main if that's necessary.
Re: Beating under headsail
Posted: Tue Jun 05, 2012 10:48 am
by Clyde_Wanderer
mm5aho wrote:I often sail with just genoa, moreso in moderate or high winds. Boat seems more balanced, and tiller is very light.
That's because the COE is moved forward of the CLR increasing the lead distance, which is the distance between the COE and CLR, this distance ideally should be a minium percentage of the waterline length to give a good balance on the rudder/helm, ideally 15 degree max tiller angle/weather helm in a moderate blow.
In other words this has the same effect as moving the keel aft.
How do I know all this?
I have had it first hand from David Thomas (Boat designer) in answering my questions why my boat suffers from such excessive weather helm, though he dident say why the HB was given as short a lead.
It appears my only cure would be to fit a bow sprit moving the COE forward.
Too much work and cost though!
C_W
Re: Beating under headsail
Posted: Tue Jun 05, 2012 9:15 pm
by Silkie
Clyde_Wanderer wrote:That's because the COE is moved forward of the CLR increasing the lead distance...
I'm sure this is the case when comparing such widely differing sail plans as main/no main but it seems to me that the standard COE/CLR argument is an over-simplification which takes no account of the sheeting position of the sails.
Ignoring the effect of sheet lead on the setting of the sail it must make a difference whether the headsail is sheeted to the quarter or further forward?
Re: Beating under headsail
Posted: Wed Jun 06, 2012 7:48 am
by ubergeekian
Silkie wrote:
Ignoring the effect of sheet lead on the setting of the sail it must make a difference whether the headsail is sheeted to the quarter or further forward?
I don't think it will, except for any effects on the shape of the sail. If the shape stays the same and you move the sheeting position, you will change the forces on forestay, fairlead and winch, but the net effects - force and moment - will be the same.
Re: Beating under headsail
Posted: Wed Jun 06, 2012 10:13 am
by marisca
ubergeekian wrote:Silkie wrote:
Ignoring the effect of sheet lead on the setting of the sail it must make a difference whether the headsail is sheeted to the quarter or further forward?
I don't think it will, except for any effects on the shape of the sail. If the shape stays the same and you move the sheeting position, you will change the forces on forestay, fairlead and winch, but the net effects - force and moment - will be the same.
I'm confused, but then that's not unusual. Can't see how you can move the sheet lead without affecting the sail set.
I quite often beat under genoa when cruising and/or pootling and agree with the feeling of balance. Pointing is not so high without the slot but so what.
Re: Beating under headsail
Posted: Wed Jun 06, 2012 1:10 pm
by cpedw
marisca wrote:Can't see how you can move the sheet lead without affecting the sail set.
I agree but I think (dangerous to try interpreting another's web statements) Silkie was speculating about the effect of moving the location where the sail's force is transferred to the boat while keeping the sail shape the same. And if my mechanical knowledge is up to the task, I think I agree with UG that it's the force on the sail that counts.
Derek
Re: Beating under headsail
Posted: Wed Jun 06, 2012 1:49 pm
by DaveS
There was a discussion on this a few years ago here:
viewtopic.php?f=1&t=3785&p=12136&hilit=genoa#p12136
which I wasted some time yesterday trying (and failing) to find before Nick helpfully pointed out the search facility...

Re: Beating under headsail
Posted: Wed Jun 06, 2012 7:37 pm
by Silkie
cpedw wrote:marisca wrote:Can't see how you can move the sheet lead without affecting the sail set.
I agree but I think (dangerous to try interpreting another's web statements) Silkie was speculating about the effect of moving the location where the sail's force is transferred to the boat while keeping the sail shape the same.
Correct - although probably impossible to achieve as Marisca says.
cpedw wrote:I think I agree with UG that it's the force on the sail that counts.
On reflection I think you're probably right. What was leading me astray was thinking only of a single attachment point which is not the case with a sail.